Sewing machine stitch length regulator



Feb 1%? E. w. BIALY ET AL SEWING MACHINE STITCH LENGTH REGULATOR Filed Jan. 28, 1964 INVENTORS. Edward W. Bia/y and Herberf J. Hurme. BY 7 United States Patent 3,303,803 SEWING MACHINE STITCH LENGTH REGULATOR Edward W. Bialy, Hillside, and Herbert J. Hurme, Elizabeth, N..i., assignors to The Singer Company, New

York, N.Y., a corporation of New Jersey Filed Jan. 28, 1964, Ser. No. 340,735 1 Claim. (Cl. 112210) This invention relates to a sewing machine stitch length regulator and has as its primary object the provision of a simple and inexpensive means for regulating the stitch length of a sewing machine.

In one class of sewing machines, a work supporting bed is provided with a hollow standard rising from one end. A hollow bracket arm is connected to the top of the standard and extends longitudinally over the bed. A main shaft is rotatably mounted within the bracket arm and extends longitudinally therethrough. A crank having a cam surface thereon is provided on an intermediate portion of the main shaft. A pitman having a fork-shaped cam follower at its top is positioned in the standard in cooperative coaction with the cam surface of the crank. A shiftable means in the form of a pivot block having a slideway therein is pivotally connected to the standard and a slide block is pivotally connected to the pitman and slidably mounted within the slideway in the pivot block.

The pivotal orientation of the ivot block slideway controls the endwise displacement of the bottom of the pitman as the crank rotates. When the slideway is tangent to a pivot at the bottom of the pitman, there will be no endwise displacement thereof, and as the crank rotates, the slide block will simply slide back and forth in the slideway without exerting any force on the pitman other than frictional force. If the slideway is oriented in any other operable position, however, the confinement of the slide block in the slideway will cause the bottom of the pitman to oscillate.

Heretofore, various means have been devised to control the pivotal orientation of the pivot block slideway and ultimately the stitch length of the sewing machine. All of these means have involved complex parts which are difficult and expensive to manufacture.

It is, therefore, an object of the invention to provide a stitch length regulator for a sewing machine which is simple in structure and inexpensive to manufacture, and which will provide for an accurate adjustment of the stitch length setting of the sewing machine.

The foregoing object of the invention is accomplished by connecting one end of a lever to the pivot block so that the free end extends through a vertical rectangular slot in the standard and describes an arc towards the standard when the lever is moved downward. The free end of the lever is threaded and receives a knob which has mating threads. An elongated sleeve having a rectangular cross section to prevent rotation in the slot in the standard is slidably mounted on the lever. Stitch length setting means, wider than the Width of the slot in the standard, are at the end of the elongated sleeve nearest to the knob on the outside of the standard. A compression spring, mounted on the lever between the pivot block and the elongated sleeve, biases the stitch length setting means against the knob. By turning the knob to move the stitch length setting means against the face of the standard, a reproducible stitch length setting is obtained.

Other objects and a fuller understanding of the invention may be had by referring to the following description and claim, taken in conjunction with the accompanying drawings in which:

FIG. 1 is a vertical cross sectional view of the standard "ice end of a sewing machine embodying the present invention,

FIG. 2 is a cross sectional view of a sewing machine of the type shown in FIG. 1, taken substantially along the line 2-2 in FIG. 1 with the knob unscrewed to its great est extent; and

FIG. 3 is a cross sectional view taken along the line 33 in FIG. 2.

With reference to the drawings, a standard 10 is connected to one end of a work supporting bed 11. A bracket arm 12 is in turn connected to the top of the standard 10 and extends longitudinally over the :bed 11 in a manner well known.

A main shaft 13 is rotatably mounted within the bracket arm 12 and extends longitudinally therethrough. A crank 14 having a three-corner cam surface thereon is provided in an intermediate portion of the main shaft 13. A pitman 15 having a fork-shaped cam follower 16 at its top is positioned in the standard 10 in cooperative coaction with the cam surface of the crank 14.

A work feeding mechanism including a shiftable means in the form of a pivot block 17 having a slideway 18 therein is pivotally connected to the standard 10 by a pivot screw 19 having a friction washer 20 thereon. A slide block 21 is pivotally connected to the pitman 15 by a pivot stud 22 and is slidab-ly embraced within the slideway 18 in the pivot block 17.

The bottom of the pitman 15 is pivotally connected to a rock arm 23 by means of an eccentric pivot screw 24. The rock arm 23 is in turn connected to a stitch length rock shaft 25 which is mounted for oscillation longitudinally within the bed 11. A pair of rock arms 26 are connected to the stitch length rock shaft 25. A feed bar 27 is pivotally connected between the rock arms 26 by means of a pivot shaft 28. A feed dog 29 is secured to the feed bar 27, and the feed bar 27 has a feed lift cam follower 39 which rides on a cam 31 on the top of a loop taker drive bar 32.

A lever 33 is connected to the pivot block 17 by a rivet-type connection 34 so that the free end extends through a vertical rectangular slot 35 in the standard 10 and describes an arc towards the standard 10 when the lever 33 is moved downward. An escutcheon or stitch length indicator plate 36 having an elongated rectangular slot 37 and having stitch length indicia 38 at each side of the slot 37, is connected to the standard It by means of screws 39 with the slots 35 and 37 in alignment.

The free end of the lever 33 is threaded as shown in FIG. 2. Threaded on the lever 33 is an insert 40 formed with external serrations, the insert being prevented from being screwed off the free end of the lever 33 by means of a split ring washer 41 and a retaining means in the form of a locknut 42. A hollow knob 43 is pressed over the external serrations of the threaded insert 40 with the locknut 42 housed inside the hollow knob 43.

An elongated sleeve 44 having a rectangular cross section is slidably mounted on the lever 33 with its rectangular cross section slidable within the slot 37 in the stitch length indicator plate 36. An indicator 45, wider than the slot 37 in the stitch length setting means plate 36, is integrally connected to the top of the elongated sleeve 44 nearest to the knob 43 on the outside of the standard 10. The stitch length setting means 45 have triangular shapes. A compression spring 46 is mounted on the lever 33 between the pivot block 17 and the elongated sleeve 44.

In operation, as the main shaft 14 rotates in the direction indicated by the arrow 47, the cam surface of the crank 14 oscillates the fork-shaped cam follower 16 of the pitman 15. As previously mentioned, when the slideway 18 is tangent to the eccentric pivot screw 24 at the bottom of the pitman 15, there will be no endwise displacement of the bottom of the pitman 15. The slide block 21 will simply slide back and forth in the slideway 18 without exerting any force on the pitman other than frictional force. If, however, the slideway 18 is oriented in any other operable position, the confinement of the slide block 21 in the slideway 18 will cause the bottom of the pitman 15 to move endwise and thus oscillate the stitch length rock shaft 25, and ultimately drive the feed dog 29 in increasing increments as the slideway 18 is pivoted away from either side of tangency to the eccentric pivot screw 24 at the bottom of the pitman 15.

The position of the lever 33 controls the orientation of the slideway 18. The ease of movement of the lever 33 can be adjusted by turning the pivot screw 19 against or away from the friction washer 20. By turning the knob 43 to move the stitch length setting means 45 against the stitch length indicator plate 36, a reproducible feed advance setting can be obtained. The Width of the stitch length setting means 45 prevents its passage through the slot 37 in the stitch length indicator plate 36. The compression spring 46 biases the stitch length setting means 45 against the insert 40 and the knob 43; and the rectangular cross section of the elongated sleeve 44, confined in the slot 37 in the stitch length indicator plate 36, prevents rotation of the elongated sleeve 44 and maintains the stitch length setting means 45 always crosswise of the slot 37 in the indicator plate 36. It is within the scope of the invention to use other means to restrain the elongated sleeve 44 against rotation than a horizontal cross section and a slot 37. The split ring washer 41 and the locknut 42 prevent the knob 43 from being turned ofi the lever 33 once the knob has been pressed onto the threaded insert 40. Thus, an extremely simple and inexpensive means has been provided for accurately regulating the stitch length of a sewing machine.

Although the invention has "been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the in vention.

What is claimed is:

A stitch length regulator for a sewing machine including a frame having an elongated rectangular slot, a work feed mechanism mounted in the frame, and shiftable means for changing the stitch length of the work feed mechanism shiftable in a direction parallel to the longitudinal edges of the slot in the frame, said stitch length regulator comprising a lever connected to the shiftable means and having external screw threads on its free end portion, an insert on the lever having internal screw threads mating with the external screw threads of the lever, retaining means on the free end of the lever for preventing the insert from being unscrewed from the lever, a knob connected to the insert and having housing means which completely enclose the retaining means to completely conceal the retaining means from view, an elongated sleeve having a longitudinal bore by which it is slidably mounted on the lever between the shiftable means and the knob and having a substantially rectangular cross section with opposite sides slidable against the longitudinal edges of the elongated rectangular slot in the frame to prevent rotation of the sleeve on the' lever, a compression coil spring mounted on the lever between the shiftable means and the sleeve for biasing the sleeve against the knob, and stitch length setting means projecting laterally from at least one of said opposite sides of the sleeve which slide against the longitudinal edges of the slot in the frame and having a triangular shape when viewed from a position substantially perpendicular to a plane described by shifting movement of the stitch length regulator with an apex of the triangle pointed toward the portion of the frame of the machine adjacent to the longitudinal edge of the slot in the frame, said stitch length setting means overlying the portion of the frame of the machine adjacent to the longitudinal edge of the slot in the frame to set the stitch length of the work feed mechanism when the lever is shifted to the de' sired position and the knob is turned so as to press the stitch length setting means against said portion of the frame of the machine adjacent to the longitudinal edge of the slot in the frame.

References Cited by the Examiner UNITED STATES PATENTS 370,805 10/1887 Mitchell 1122l0 2,024,434 12/1935 Eames 1l22l0 2,931,329 4/1960 Johnson ll2210 JORDAN FRANKLIN, Primary Examiner.

RICHARD J. SCANLAN, JR., Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No: 3,303,803 February 14, 1967 Edward W. Bialy et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, Iine 59, strike out "An indicator" and insert instead A stitch length setting means line 60, for "setting means" read indicator Signed and sealed this 17th day of October 1967.

(SEAL) Attest:

EDWARD J. BRENNER Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer 

